Interspinous spacers are indicated for the treatment of spinal stenosis and treatment of low back pain caused by, for example, disc- or facet-related degeneration. Interspinous spacers may be configured to distract and/or maintain the spacing between adjacent superior and inferior spinous processes above and below the painful disc level.
Most interspinous spacers in clinical use are made of a hard, undeformable material under normal physiological loads, such as metal or PEEK. There is an increasing concern, supported by recent clinical study data, that suggests hard spacers may subside into the bony spinous processes over time, thus losing their therapeutic effect. Softer spacers could potentially avoid subsidence by distributing loads over a larger area of the spinous processes. Moreover, soft spacers may be gentler to the portions of the bony spinous processes between which they interface.
Further, inflatable interspinous spacers may be desirable in that they may be well-suited for a truly percutaneous solution that may enable tissue damage, the size of the surgical incision and the resultant risk of infection and recovery time to be minimized.